Heretofore, in an automated assembly line for automobiles, clamping by a clamp apparatus has been carried out, in a state in which pre-formed body panels are overlapped and positioned, and an assembly step is carried out whereby the body panels are welded together.
The present applicant has proposed an electric clamp apparatus, as disclosed in Japanese Laid-Open Patent Publication No. 2005-169604. In such an electric clamp apparatus, a clamp arm is disposed rotatably on a body equipped with an electric motor, and by transmitting a rotary driving force of the electric motor through a speed-reducing drive system, the clamp arm is rotated to clamp a workpiece.